It's been a year since state Rep. Isaac Latterell rolled his eyes and put his hand over his face in an act of protest against the Republican National Convention's support for then-candidate Donald Trump.

Now, six months into the president's first term in office, Latterell, a Tea Republican, said he still disapproves of the GOP leader.

"He's been drowning in the D.C. swamp and failing on his promise to drain it," Latterell said.

Latterell represented South Dakota at the 2016 Republican National Convention and was among the 29 delegates who cast the state's votes for Trump. But the Ted Cruz supporter made clear that he wasn't happy about the party's decision.

“I just think that it’s a sad day for the Republican Party," Latterell said in a phone interview following the 2016 convention. "I don’t think that the candidate that was chosen has a chance of winning the election, or being different than the other nominee."

Latterell said Tuesday that Trump exceeded his expectations in beating Democrat Hillary Clinton, rolling back restrictions on domestic energy producers and following through on his promise to nominate a conservative to the Supreme Court.

But he said the president had fallen flat on promises to repeal the Affordable Care Act, pass a budget or bring tax reform.

Rather than pushing against the Republican establishment and GOP leaders in Congress, Trump joined them once he took office, Latterell said.

"I could see who he really was and what was behind all the things he was saying and a lot of other people were believing him," he said. "I think he's a result of the problem, but he isn't the solution."